package com.jiandp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.jiandp.dto.Result;
import com.jiandp.entity.Shop;
import com.jiandp.mapper.ShopMapper;
import com.jiandp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.jiandp.utils.CacheClient;
import com.jiandp.utils.RedisConstants;
import com.jiandp.utils.RedisData;
import com.jiandp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.ExceptionHandler;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.jiandp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);
        //逻辑过期解决缓存击穿
      //  Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);

        if (shop==null){
            return Result.fail("店铺不存在!");
        }


        //7.返回
        return Result.ok(shop);
    }

    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

   /* public Shop queryWithLogicalExpire(Long id){
        //1.从redis中查询店铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isBlank(shopJson)){
            //3.存在返回数据
            return null;
        }
        //4 命中需要把Json反序列化成对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        JSONObject data = (JSONObject) redisData.getData();
        Shop shop = JSONUtil.toBean(data, Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();

        //5判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())){
            //5.1 未过期直接返回数据
            return shop;
        }

        //5.2 过期需要缓存重建
        //6缓存重建
        //6.1获取互斥锁
        String lockKey=LOCK_SHOP_KEY+id;
        boolean isLock = tryLock(lockKey);
        //6.2判断获取锁其否成功
        if (isLock){
            // 【Double Check】再次检查缓存是否已被其他线程重建
            String latestShopJson = stringRedisTemplate.opsForValue().get(key);
            if (StrUtil.isNotBlank(latestShopJson)) {
                RedisData latestRedisData = JSONUtil.toBean(latestShopJson, RedisData.class);
                if (latestRedisData.getExpireTime().isAfter(LocalDateTime.now())) {
                    // 缓存已被重建，直接释放锁并返回最新数据
                    unLock(lockKey);
                    return JSONUtil.toBean((JSONObject) latestRedisData.getData(), Shop.class);
                }
            }
            //6.3成功，开启独立线程实施缓存重建
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    //重建缓存
                    this.saveShop2Redis(id,20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }finally {
                    //释放锁
                    unLock(lockKey);
                }

            });
        }

        //6.4失败返回过期的商品信息

        //7.返回
        return shop;
    }*/

  /*  public Shop queryWithMutex(Long id){
        //1.从redis中查询店铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(shopJson)){
            //3.存在返回数据

            return JSONUtil.toBean(shopJson, Shop.class);
        }
        if (shopJson!=null){
            return null;
        }
        String lockKey= null;
        Shop shop = null;

        try {
            //4.实现缓存重建
            //4.1 获取互斥锁
            lockKey = LOCK_SHOP_KEY+id;
            boolean isLock = tryLock(lockKey);
            //4.2 判断是否获取成功
            if (!isLock){
            // 4.3 失败，休眠并重试
                Thread.sleep(50);
               return queryWithMutex(id);
            }

            if (StrUtil.isNotBlank(shopJson)) {
                // 缓存已存在，直接返回
                return JSONUtil.toBean(shopJson, Shop.class);
            }

            // 4.4 成功查询数据库
            // 不存在，查询数据库
            shop = getById(id);
            //模拟重建延迟
            Thread.sleep(200);
            if (shop == null) {
                //5.不存在返回错误
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;

            }
            //6.存在，查询并建立缓存
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //释放互斥锁
            unLock(lockKey);
        }

        //8.返回
        return shop;
    }*/


    /*public Shop queryWithPassThrough(Long id){
        //1.从redis中查询店铺缓存
        String key = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(shopJson)){
            //3.存在返回数据

            return JSONUtil.toBean(shopJson, Shop.class);
        }
        if (shopJson!=null){
            return null;
        }

        //4.不存在，查询数据库
        Shop shop = getById(id);
        if (shop == null) {
            //5.不存在返回错误
            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;

        }
        //6.存在，查询并建立缓存
        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //7.返回
        return shop;
    }*/

  /*  private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }
    private void  unLock(String key){
        stringRedisTemplate.delete(key);
    }


    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        //查询店铺数据
        Shop shop = getById(id);
        Thread.sleep(200);
        //封装逻辑时间
        RedisData redisData=new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,JSONUtil.toJsonStr(redisData));
    }*/

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id ==null){
            return Result.fail("店铺id不能为空");
        }
        //更新数据库
        updateById(shop);
        //删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要坐标查询
        if (x==null||y==null){
            Page<Shop> page =query()
                    .eq("type_id",typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            return Result.ok(page.getRecords());
        }

        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

// 3.查询redis、按照距离排序、分页。结果：shopid、distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() // GEOSEARCH key
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );

// 4.解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size()<=from){
           return Result.ok(Collections.emptyList());

        }
// 4.1.截取 from ~ end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            // 4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });

        //5.根据id查询Shop
        String idStr =StrUtil.join(",",ids);
        List<Shop> shops = query().in("id",ids).last("ORDER BY FIELD(id,"+idStr+")").list();
        for (Shop shop:shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shops);
    }
}
